The present invention relates to a fiber optic mixing device for mixing optical signals inputted from a plurality of optical fibers.
FIG. 1 shows the construction of an example of a conventional optical mixing device. In this figure, reference numerals 11 to 15 designate multicore optical fibers of a type used in communications, ends of which are connected to an optical glass 2 at respective prescribed positions. Reference numeral 3 denotes an output single optical fiber connected to the optical glass 2.
An optical signal carried by a laser beam is imputted to each of the optical fibers 11 to 15. The laser beams emitted from the respective optical fibers 11 to 15 are made incident on the optical glass 2 and are mixed therein. The resultant mixed laser beam is outputted so as to enter the single optical fiber 3.
FIG. 2 shows the construction of another example of a conventional fiber optic mixing device. In this figure, reference numeral 31 denotes an optical fiber of an input trunk line, and reference numeral 32 denotes an optical fiber of an output trunk line. Reference numerals 41 to 43 represent half mirrors.
Laser beams emitted from optical fibers 11 to 13 are reflected by the corresponding half mirrors 41 to 43 and are mixed with an input laser beam from the optical fiber 31 and then outputted to the optical fiber 32.
However, the first conventional fiber optic mixing device mentioned above is costly because of the use of the expensive optical glass. Further, since the connecting positions on the optical glass to receive the input optical fibers are limited, the device unavoidably becomes large when a large number of optical fibers are connected to the optical glass.
On the other hand, in the second conventional fiber optic mixing device, the use of the half mirrors incurs such problems that when many optical fibers are connected to the optical glass the device becomes large, complicated and so costly.